Dominant Background color extraction in Images

Aug, 2013

Following is a continuation to my github project at https://github.com/karthik20522/DominantBackgroundColor

The problem of background color extraction hit me when I was trying to dynamically set background color based on dominant color of the image which usually is background color. Part of my solution was to average out the colors and perform a histogram equalization to extract a dominant color.

Since there are 255 x 255 x 255 possible combinations of colors it would more useful to reduce the result to more limited color space. For example if you want to provide filtering or sorting functionality of images with particular color it would be more user friendly to provide a limited/controlled set of color options instead of displaying 100's or 1000's of colors for the user to pick! In this project I used monochrome values of rainbow colors as my closest matching color subset for matching purposes.

Following is some examples of how the code performed:


Result	Result	Result	Result

There are two main functions in the code that can be utilized:

1. To Extract the most dominant color in the image:


       //This function would return the most dominant color in the image. The examples above are the result of this function
   var dominantHTMLColor = await new DominantColor().GetDominantColor(imageURI);

2. Convert the dominantHTMLColor to a smaller subset result


       //This function would return the closest match to rainbow colors
    var closestHTMLColor = _dominantColor.GetClosestColor(dominantHTMLColor);

Examples of the above Subset/Closest match code:


Actual	Actual	Actual	Actual
Subset	Subset	Subset	Subset

For the most part the results are very close to the original dominant color. The whole idea was to match the resulting dominant color to one of the following rainbow colors:

But what if you want the code to return a list of top 5 colors. Well, you can modify the code as per your requirement by making this simple change to the linq query (which is currently set to pick the top color):


    var colorsWithCount = GetPixels(bitmap)
    .GroupBy(color => color)
    .Select(grp =>
        new
        {
            Color = grp.Key,
            Count = grp.Count()
        })
    .OrderByDescending(x => x.Count)
    .Take(5); //take top 5 color